Recommended Samples and other settings to remove fireflies?
A great way to reduce the number of fireflies is to clamp. In the Render panel, under Sampling, you'll see Clamp Indirect. This will remove any bright pixels (fireflies). Start with a high value, maybe 1-3. Then work your way down until all the fireflies are gone. Clamping does darken your render, so it's important to use the highest number possible so that you keep as much brightness as possible.

32 samples, no clamp

32 samples, .5 clamp
You can further reduce the noise with more sampling, or, you can use denoising if you are in a dev version.